scholarly journals Hardness Modulated Thermoplastic Poly(ether ester) Elastomers for the Automobile Weather-Strip Application

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 525
Author(s):  
Su Hyeon Jeon ◽  
Jae Eon Jeong ◽  
Seongkyun Kim ◽  
Sungwan Jeon ◽  
Jin Woo Choung ◽  
...  
Keyword(s):  
Hard Segment ◽  
Soft Segment ◽  
Acid Amide ◽  
Chain Extender ◽  
New Material ◽  
Phase Separation Behavior ◽  
Separation Behavior ◽  
Ether Ester ◽  
Long Chain Branch ◽  
Chain Branch

As a means of developing new material for automobile weather-stripping and seal parts replacing the conventional ethylene propylene diene monomer rubber/polypropylene vulcanizate, a series of poly(ether ester) elastomers are synthesized. The hardness is modulated by controlling chain extender composition after fixing the hard segment to soft segment ratio. Targeted hardness is achieved by partly substituting conventional chain extender 1,4-butandiol for soybean oil-originated fatty acid amide diol that bears a long chain branch. The crystallinity and phase separation behavior resultant elastomer are also tunable simply by modulating chain extender composition and hard to soft segment ratio.

scholarly journals The influence of hard segment content on mechanical and thermal properties of polycarbonate-based polyurethane materials

2012 ◽  
Vol 66 (6) ◽  
pp. 853-862 ◽  
Author(s):  
Jelena Pavlicevic ◽  
Milena Spirková ◽  
Jaroslava Budinski-Simendic ◽  
Mirjana Jovicic ◽  
Oskar Bera ◽  
...  
Keyword(s):  
Phase Separation ◽  
Hard Segment ◽  
Soft Segment ◽  
Chain Extender ◽  
Melting Enthalpy ◽  
Degree Of Crystallinity ◽  
Elongation At Break ◽  
Hard Segment Content ◽  
Hard Segments ◽  
Polycarbonate Diol

Aliphatic segmented polyurethanes were prepared by one-step procedure in catalytic reaction between polycarbonate diol, hexamethylene-diisocyanate and 1,4-butandiol (as chain extender). The hard segment content TS was varied (17, 24, 30 and 42 wt. %) by changing the ratio of starting compounds. The soft segment is made from flexible aliphatic polycarbonate diol, while hard segments consist of chain extender and diisocyanate component. In order to study the hydrogen bonding formation and phase separation, Fourier transform infrared spectroscopy (FT-IR) was used. Wide angle X-ray scattering (WAXS) was performed to determine a degree of crystallinity and to investigate the phase behavior of prepared elastomers. The effect of TS content on mechanical properties (tensile strength, elongation at break and hardness) was tested. Thermal behavior of prepared novel polycarbonate-based polyurethanes was investigated using differential scanning callorimetry (DSC). It was determined that the elastomer which contains the highest amount of urethane groups in its structure (TS content of 42 wt. %) exhibits the most pronounced phase separation and the highest degree of crystallinity. All prepared polyurethanes exhibit high elongation at break (over 700%). The glass transition temperature Tg of prepared samples was in the temperature region from ?39 to ?36?C, and it was found to be slightly influenced by the soft segment content. The enthalpy of chain segments relaxation in diffused region between hard and soft domains (detected in the temperature range from 35 to 55 ?C) was decreased with the increase of hard segment content. The multiple melting of hard segments (connected with the dissruption of physical crosslinks) appeared above 100 ?C. It was found that the melting enthalpy linearly increases with the increase of urethane group content. Sample with 42 wt. % of TS has the highest value of melting enthalpy (41.5 J/g).

scholarly journals Synthesis and Properties of Novel Polyurethanes Containing Long-Segment Fluorinated Chain Extenders

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1292 ◽  
Author(s):  
Jia-Wun Li ◽  
Hsun-Tsing Lee ◽  
Hui-An Tsai ◽  
Maw-Cherng Suen ◽  
Chih-Wei Chiu
Keyword(s):  
Hard Segment ◽  
Soft Segment ◽  
Mechanical Analysis ◽  
Chain Extender ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Chain Extenders ◽  
Relationship Of ◽  
The Relationship

In this study, novel biodegradable long-segment fluorine-containing polyurethane (PU) was synthesized using 4,4′-diphenylmethane diisocyanate (MDI) and 1H,1H,10H,10H-perfluor-1,10-decanediol (PFD) as hard segment, and polycaprolactone diol (PCL) as a biodegradable soft segment. Nuclear magnetic resonance (NMR) was used to perform 1H NMR, 19F NMR, 19F–19F COSY, 1H–19F COSY, and HMBC analyses on the PFD/PU structures. The results, together with those from Fourier transform infrared spectroscopy (FTIR), verified that the PFD/PUs had been successfully synthesized. Additionally, the soft segment and PFD were changed, after which FTIR and XPS peak-differentiation-imitating analyses were employed to examine the relationship of the hydrogen bonding reaction between the PFD chain extender and PU. Subsequently, atomic force microscopy was used to investigate the changes in the microphase structure between the PFD chain extender and PU, after which the effects of the thermal properties between them were investigated through thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. Finally, the effects of the PFD chain extender on the mechanical properties of the PU were investigated through a tensile strength test.

scholarly journals Effect of Nanofiller Dispersion on Morphology, Mechanical and Conducting Properties of Electroactive Shape Memory Poly(Urethane-Urea)/Functional Nanodiamond Composite

2015 ◽  
Vol 15 (4) ◽  
pp. 14-28 ◽  
Author(s):  
A. Kausar
Keyword(s):  
Electrical Conductivity ◽  
Tensile Strength ◽  
Shape Memory ◽  
Shape Recovery ◽  
Hard Segment ◽  
Soft Segment ◽  
Chain Extender ◽  
Solution Casting ◽  
Melt Blending ◽  
Solution Route

Abstract In this attempt, segmented poly(urethane urea) was prepared from polycaprolactone triol (soft segment), 1,3- bis(isocyanatomethyl)cyclohexane (hard segment) and 4,5-diaminophthalonitrile (chain extender). Acidfunctionalized nano-diamond was used as nano-filler. The nanocomposites were processed using solution casting and melt blending. Unique morphology was observed by SEM due to generation of crosslinked polyurethane and ND network. The s-PUU/ND 10 depicted 6 % increase in tensile strength compared with m-PUU/ND 10. 10 wt. % ND loading via solution route increased conductivity to 0.089 Scm-1 relative to m-PUU/ND 10 (0.057 Scm-1). Electrical conductivity of nanocomposites was enough to show electroactive shape recovery of 95 % (40 V).

Effect of Catalysts on the Properties of Fluorinated Polyurethanes

2013 ◽  
Vol 464 ◽  
pp. 9-13 ◽  
Author(s):  
Zan Li ◽  
Xia Wang ◽  
Ying Li ◽  
Wei Chain ◽  
Jiao Jiao Hu
Keyword(s):  
Hard Segment ◽  
Soft Segment ◽  
Force Microscopy ◽  
Atomic Force ◽  
Structure Surface ◽  
Improved Stability ◽  
Ft Ir ◽  
Tin Metal ◽  
Polyether Polyol ◽  
Catalyst Efficiency

Fluorinated polyurethanes (FPU) was prepared using fluorinated polyether polyol (FPO) as the soft segment, 4,4`-diphenylmethane diisocyanate (MDI) as the hard segment, 1,4-butanodiol (BDO) as the chain extender and catalysts. Tin metal catalysts were used to catalyze the polyurethane reaction of polyether polyols and isocyanate. The effect of different catalysts including stannous octoate (T-9) and dibutyltindalautrate (DBTDL) on the structure, surface properties and thermal properties of FPU was studied. The structural elucidation of the synthesized FPU was performed by Fourier transform infrared (FT-IR) and discovered that with decreasing catalyst efficiency or without catalyst, the strength of hydrogen bounds were enhanced. The FPU films surface was characterized by contact angle (CA) and atomic force microscopy (AFM) and it was found that the phase separation was increasing with increasing catalyst efficiency. The thermal property was exhibited by Thermo gravimetric (TG) and showed that joining catalyst improved stability significantly.

Phase Separation Behavior of Fusidic Acid and Rifampicin in PLGA Microspheres

2012 ◽  
Vol 9 (5) ◽  
pp. 1489-1501 ◽  
Author(s):  
Samuel E. Gilchrist ◽  
Deborah L. Rickard ◽  
Kevin Letchford ◽  
David Needham ◽  
Helen M. Burt
Keyword(s):  
Phase Separation ◽  
Fusidic Acid ◽  
Plga Microspheres ◽  
Phase Separation Behavior ◽  
Separation Behavior
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